In recent times a television broadcasting system has been developed which has an enlarged screen aspect ratio of 16:9. A television signal of a wide aspect ratio is hereinafter referred to as a wide aspect signal. A viewer's sense of presence can be enhanced on a wide aspect screen.
In order to achieve a wide aspect screen, it is necessary to consider a compatibility between a current television broadcasting system (aspect ratio of 4:3) signal and a wide aspect signal. Stated in another way, a new broadcasting system needs to be developed to reproduce a wide aspect signal even if being transmitted on a current television receiver.
A new broadcasting system has been developed which divides a wide aspect screen into a center panel and side panels, transmits a center panel signal (hereinafter referred to as a center signal) and side panel signal (hereinafter referred to as side signals) in separate channels, and reproduces two channel signals on a receiving side and assembles one wide aspect ratio signal. According to the new broadcasting system, if only a center signal's panel is employed, it is possible to receive and reproduce a center signal in the channel on a current television receiver.
However, this new system requires two channels for transmitting a wide aspect signal and tuners also on the receiving side for reception in two channels.
It is accordingly an object of this invention to provide an addition signal multiplexing apparatus for a television system which can transmit center and side signals in one channel with the side channels time division multiplexed on overscan areas of the center signal.
Another object of the present invention is to provide an addition signal mulplexing apparatus for a television system which, upon the time division multiplexing of side signals on overscan areas, multiplexes the side signals on the overscan areas of those fields proceeding relative to the field of a center signal corresponding to the side signal and, when the reproduction of the side signal has been completed, starts the reproduction on the screen of the center signal corresponding to the side signal to suppress an increase of a delay memory (hardware) on a decoder side.
Another object of the present invention is to provide an addition signal multiplexing apparatus for a television system which can transmit side signal information without leakage in which, when intermittently delivered side signals are joined in a continuous form and time division multiplexed on vertical overscan areas, the side signals are processed to enable a high correlative area of the side signal to be processed at the joined point of the side signal.